A. Fleerhttp://repub.eur.nl/ppl/4725/
List of Publicationsenhttp://repub.eur.nl/eur_signature.pnghttp://repub.eur.nl/
RePub, Erasmus University RepositoryMoraxella catarrhalis: From emerging to established pathogenhttp://repub.eur.nl/pub/55272/
Mon, 21 Jan 2002 00:00:01 GMT<div>C.M. Verduin</div><div>C. Hol</div><div>A. Fleer</div><div>H.A. van Dijk</div><div>A.F. van Belkum</div>
Moraxella catarrhalis: from emerging to established pathogenhttp://repub.eur.nl/pub/9821/
Tue, 01 Jan 2002 00:00:01 GMT<div>C.M. Verduin</div><div>C. Hol</div><div>A. Fleer</div><div>H. van Dijk</div><div>A.F. van Belkum</div>
Moraxella catarrhalis (formerly known as Branhamella catarrhalis) has
emerged as a significant bacterial pathogen of humans over the past two
decades. During this period, microbiological and molecular diagnostic
techniques have been developed and improved for M. catarrhalis, allowing
the adequate determination and taxonomic positioning of this pathogen.
Over the same period, studies have revealed its involvement in respiratory
(e.g., sinusitis, otitis media, bronchitis, and pneumonia) and ocular
infections in children and in laryngitis, bronchitis, and pneumonia in
adults. The development of (molecular) epidemiological tools has enabled
the national and international distribution of M. catarrhalis strains to
be established, and has allowed the monitoring of nosocomial infections
and the dynamics of carriage. Indeed, such monitoring has revealed an
increasing number of B-lactamase-positive M. catarrhalis isolates (now
well above 90%), underscoring the pathogenic potential of this organism.
Although a number of putative M. catarrhalis virulence factors have been
identified and described in detail, their relationship to actual bacterial
adhesion, invasion, complement resistance, etc. (and ultimately their role
in infection and immunity), has been established in a only few cases. In
the past 10 years, various animal models for the study of M. catarrhalis
pathogenicity have been described, although not all of these models are
equally suitable for the study of human infection. Techniques involving
the molecular manipulation of M. catarrhalis genes and antigens are also
advancing our knowledge of the host response to and pathogenesis of this
bacterial species in humans, as well as providing insights into possible
vaccine candidates. This review aims to outline our current knowledge of
M. catarrhalis, an organism that has evolved from an emerging to a
well-established human pathogen.Persistence of clones of coagulase-negative staphylococci among premature neonates in neonatal intensive care units: two-center study of bacterial genotyping and patient risk factorshttp://repub.eur.nl/pub/8879/
Thu, 01 Jan 1998 00:00:01 GMT<div>C.L. Vermont</div><div>N.G. Hartwig</div><div>A. Fleer</div><div>P. de Man</div><div>R. de Groot</div><div>A.F. van Belkum</div><div>H.A. Verbrugh</div><div>J.N. van den Anker</div>
From 1 January 1995 until 1 January 1996, we studied the molecular
epidemiology of blood isolates of coagulase-negative staphylococci (CoNS)
in the Neonatal Intensive Care Units (NICUs) of the Sophia Children's
Hospital (SCH; Rotterdam, The Netherlands) and the Wilhelmina Children's
Hospital (WCH; Utrecht, The Netherlands). The main goal of the present
study was to detect putatively endemic clones of CoNS persisting in these
NICUs. Pulsed-field gel electrophoresis was used to detect the possible
presence of endemic clones of clinical significance. In addition, clinical
data of patients in the SCH were analyzed retrospectively to identify risk
factors for the acquisition of positive blood cultures. In both centers,
endemic CoNS clones were persistently present. Thirty-three percent of the
bacterial isolates derived from blood cultures in the SCH belonged to a
single genotype. In the WCH, 45% of all bacterial strains belonged to a
single clone. These clones were clearly different from each other, which
implies that site specificity is involved. Interestingly, we observe that
the clonal type in the SCH differed significantly from the incidentally
occurring strains with respect to both the average pH and partial CO2
pressure of the patient's blood at the time of bacterial culture. We found
that the use of intravascular catheters, low gestational age, and a long
hospital stay were important risk factors for the development of a
putative CoNS infection. When the antibiotic susceptibility of the
bacterial isolates was assessed, a clear correlation between the nature of
the antibiotics most frequently used as a first line of defense versus the
resistance profile was observed. We conclude that the intensive use of
antibiotics in an NICU setting with highly susceptible patients causes
selection of multiresistant clones of CoNS which subsequently become
endemic.